The next critical thing to watch for are report on what US casualties there are

Iran has fired multiple missiles against multiple targets inside Iraq

In an operation as revenge for the killing of Qassem Soleimani

What will be critical to any US response will be casualty numbers. As yet, there are no official reports on these. US casualties will prompt an escalation from Trump. Trump has already said (earlier this week) that his response to Iran may be disproportionate.

Added:

• Iran said to have fired 35 missiles at the Al-Assad airbase in Iraq